1. Field of the Invention
This invention relates to fluorocarbon dye dispersions and to the exhaust dyeing of synthetic polymers therewith.
2. Description of the Prior Art
It has been recognized in the art that there is an advantage in carrying out dyeings on synthetic fibers using disperse type dyes in nonaqueous systems. Such processes have lower energy requirements, due to the lower specific heats and heats of vaporization of organic solvents, than processes employing water. It also has been recognized that exhaust dyeing from organic solvents carries with it certain inherent limitations. It is known that the degree of dyeing in exhaust procedures depends on the partition function of the dye between the dyeing medium and the fiber. In aqueous systems this function favors the fiber because of the low solubility of disperse dyes in water. In organic solvents the favorable partition function of aqueous systems is often lost or at least decreased because the dyes tend to be considerably more soluble in the organic solvents than in water. Gebert in Melliand Textilberichte, 52 (6), 710-715 (1971) discloses that for dyeing from perchloroethylene the dye must have low solubility in the solvent. German Pat. No. 2,002,286 discloses the use of certain specific halogenated methanes or ethanes having poor dye solvent properties, such as 1,1,2-trichloro-1,2,2-trifluoroethane, monofluorotrichloromethane or 1,2-dichloro-1,1,2,2-tetrafluoroethane. Since the dyeings are carried out at relatively low temperatures with these solvents, heat fixation of the dyes in the fibers is usually achieved by the well known dry heat or Thermosol technique. Such a method, therefore, involves a two step process.